GrantB

A friend of mine is selling a C6Z with a bunch of nice parts: WC hood, nice wheels, Motons, Brembos, Burns Stainless mufflers, and a twin-disc clutch. It's got ~15k miles.

I'm in the market for a car which can be driven to a track, lapped mercilessly, then driven home (though it would sometimes be trailered, I live near a track). I'm an experienced driver and I like to drive hard, so I know the factory LS7 wouldn't last. I wasn't considering a C6Z because of the reliability issues, but this car is really clean and he's offering me a good deal. It's much cheaper than the other cars I was looking at.

It's my understanding the car would at least need:

• Aftermarket heads, or at least one-piece valves
• A larger capacity dry sump tank (it's a 2008)
• Oil pan baffle
• Better radiators and oil coolers
• Higher volume scavenge pump
• Some rod work or new rods. I know many of the Ti rods are out of round on the big ends.
• Solid control arm bushings
• Maybe a lower rev-limiter
• Anything else?

Are there any shops you guys would recommend to make a C6Z bullet-proof? I have neither the time nor desire to take on this project myself - I'd only do it if a good shop could handle the work and it fits within my overall budget.

Thanks for any help.

blkbrd69

http://www.xplosiveperformance.com/

Mordeth

My suggestions are italicized. I've helped alot of guys on this forum setup their C6Z for HPDE, tracking and racing. Happy to help if I can. If you do purchase the car I am also happy to chat offline if that is easier (email or phone).

• Aftermarket heads, or at least one-piece valves:No need. Send OEM castings to AHP (American Heritage Performance) and have them perform their Stage 4 upgrade with Moldstar 90 guides. Also have them upgrade your OEM rocker arms with CHE bushings. Heads will now be effectively bullet proof for quite some time.
• A larger capacity dry sump tank (it's a 2008): Send your tank to Lingenfelter to have them weld on an added section for 3 more quarts. And while you are doing that purchase AVIAID tank insert.
• Oil pan baffle: Purchase Improved Racing Oil pan baffle
• Better radiators and oil coolers: Purchase Dewitts radiator. Purchase Improved Racing Oil cooler, lines and 212 degree thermostat (it is a kit)
• Higher volume scavenge pump: Purchase Katech Red pump
• Some rod work or new rods. I know many of the Ti rods are out of round on the big ends: Not needed. The pistons are the weak point, not the rods.
• Solid control arm bushing: Purchase AMT Monoballs (best there is)
• Maybe a lower rev-limiter: No need for this
• Anything else: Yes, safety items such as proper race seats (Sparco Ergo), proper seat mounts (AMT), Harness bar (Brey-Krause) 6 point harness (Schroth) and Hans Device. I would also suggest AMT motor mounts (stock mounts are **** and will fail. AMT Camber kit (stock eccentrics will slip and alignment settings will change). Lots of other things as well, like power steering pump (OEM will fail, buy Turn-one), starter (wrap with heat shield), shifter (upgrade to MGW) and the list goes on and on.

c5racr1

GrantB

Mordeth, thanks for the excellent suggestions!

I already have a lot of safety gear, like expired Schroth harnesses. Do you know if a Sparco Ergo 2 large seat on the AMT mounts can fit in a C6Z?

Also, how well does the dry sump system work with all those upgrades? Can you run aero and R-compounds without external scavenge pumps?

blkbrd69, thanks! Those guys are near me. I'll stop in and check out their shop the next time I'm in the area.

Mordeth

Well, no matter what you do to modify the existing system it will never be a proper drysump like a Dailey or ARE (which come with their own set of issues). However, you can make the OEM oiling system more or less bullet proof and reliable with what I listed above and you will have no issues on R-comps. As a reference, I pretty much run what I listed above and my car has full aero, full suspension, is on Hoosier R7s and I turn 1:58 at Watkins Glen, which is good enough for 1st place this recent weekend at a NASA race. No oiling issues driven 10/10ths at race speed on Hoosiers or slicks. If you research my posts on here there are pictures and info on my setup.

I am not sure if the Sparco Ergo Large will fit, but I suspect they will. Mine are the regular size and fit with no major problems (there are always a million tiny issues though that need resolving once you start modifying things). You may need to take some measurements though to be sure. Reference this thread for seats that are known to fit in Corvettes: https://www.corvetteforum.com/forums...ar-thread.html

And reference the attached pdf that is a sizing chart for Sparco seats.

Glowing Rotors

Another thing is to remove the thermostat and block the water pump bypass. From memory a 1.125 inch freeze plug works well and you don't have to remove the water pump to install it. This forces all the water through the radiator all the time. On cool days you need to let it idle a while to warm up a bit before going hard....

Bill Dearborn

Can't argue with this recommendation. All of those items are excellent. However, I ran my 08 C6Z without all of that stuff. The big issue is the engine and you need to do something about the heads. The rest of the stuff will work in stock form. Even after I moved South from NY State to North Carolina and ran in some hotter temps I never had an oil temperature issue with the engine. Oil temps ran around 260 and coolant temps around 230 on hot days. For 6 years I ran slicks with the stock oiling system and didn't have an issue with oil supply to the engine since I managed revs in turns and didn't run on tracks that long high G left hand turns on them. The stock 8 quart system works fine as long as you stay away from those long high G left hand turns.

One thing I think needs to be addressed right up there with the engine is the brakes. The stock stuff is junk and you want something reliable to slow you down over and over again. Besides the valve train I had the most trouble with the brakes and they are the thing that came close to killing me due to sudden brake failure at very bad times. I used the Shark Bar Vs the BK bar and had race seats that I used when on track. I took them out and used the stock seats on the roads. The stock seats are made for large butts and beer bellies and have no lateral support even if you update them with inflatable side bolsters.

The stock motor mounts tend to fail quite often so changing those is a good idea. The camber plates aren't really required but do make things easier since you can set the alignment and pretty much forget about it. I had two settings street and race and all it did was take flipping camber plates around on the mounting bolt and resetting toe to change from one to the other.

That 7K rev limiter is nice, do everything to make sure you can keep it. I had an engine drop a valve on track (at the Glen) and GM replaced it under warranty. When I had the second engine checked 4 years later two of the intake valves were slightly out of spec so had new heads with Ti/Mo intake and exhaust valves installed along with bronze guides (basically the Katech recommendation). I even used stock valve springs. The updated engine had no issues going all the way to 7 grand.

Bill

jbondfl

JDIllon

The guys at xplosiveperformance do a great job and I would highly recommend them. Bill Dearborn and myself and many others have run C6Zs for many years with great results. You don't have to go crazy with engine work to have a fast reliable track car. But the brakes need to be addressed!!! I ran Stoptech's but I think Jeff at Essex https://www.essexparts.com/ probably has the best setup now. Just my .02 JD

Cyber Greg

I have a GS but some of this stuff is universal:
Jeff at Essex can set you up with an AP Racing BBK that works great.
I run Ferodo DS1.11 and they wear very nicely.
The Dewitts radiator also helps quite a bit. I can run 30 minute sessions in the summer now.
I'm very happy running the new Toyo R888R's. Very predictable slip and decent wear. I'm running a 345 rear on 19" rim. Fits perfectly. Run them hot at 36 psi.
I like the Brey Krause bar.
My main track is Willow Springs. I run 1:30's at the moment.

xene106

Definitely interested in all the information provided. Just picked up a c6z myself and would like to make a track car/time attack car someday. Currently track an S2000.

Do the newer C6zs with the larger dry sump tank still require extensive oiling upgrades?
What is the issue with stock brembo lick 6 piston brake system?

Motor mount issue was new to me so that is easy to address luckily.

Dropspeed

GS/Z06 brakes burn to the ground when used hard at the track. I swapped mine to the Essex /AP kits front and rear and could not be happier

My car is a HPDE / Time attack car that weighs 3596 (full tank w/me).
I run the DS UNO pads

CP9660 / 355mm P/N: 13.01.10025 F
CP9449 / 340mm P/N: 13.01.10059 R

Change the motor mounts before you break one and the fluid leak/burns on the engine.

-Matt

blackbeast99

I track my car at 9-10/10ths as well, but usually only for 10-15 sessions max...and not all day long or really during the summer months in GA for lots of reasons. It is also still street legal.

I run a few DE's per year, no racing or time trials, and I also instruct with Chin Motorsports.

However that being said, I've done the following to my car and have run a best 1.32 at Road Atlanta:

• Vengeance Racing built block (stock block forged/beefed up a little) - Wiseco forged pistons, Katch rod bolts, WCCH heads (Ti intake valves, stainless exhaust valves) ZR1 oil pump, hardened pushrods, expanded oil tank, etc.
• SKF hubs/bearings
• Hoosier A7's
• Stock calipers/carbotech pads
• Stock Aero
• Stock suspension
• Stoptech slotted rotors
• Motul 660 fluid/Stainless lines
• Royal purple fluids (oil, diff)
• Harness/HANS/OMP seat

I ran my car stock for a couple of years (excluding brake pads/lines/fluid) on R888's. So there isn't much to do to these cars...or there is...depends how extreme you want to be/how you drive, etc...I'm right in the middle.

CaddyRacer

What about front control arm bushings?
I had a front set of arms replaced on my 2012 C6Z with 40k miles

I understand I can replace the front only bushings with Delrin or solid
My Z is still my street car so I can go 100% race car

Has anyone replaced their front bushings?
…if yes which way did you go?
……how is the street noise?

carefulnow

I wouldn't recommend a 6 point w/o a cage, and specifically one that puts the main hoop high enough to properly clear (+ margin) the helmet when seated. This is typically not something done correctly in cage builds you tend to see on this forum i.e., when the main hoop isn't at the same level or higher than the original halo of the car. For folk over (a guess) 5'5" ish, this usually involves removing the halo of the car unless you are a VERY short driver and can thus position your seat very far forward (allowing a main hoop of correct height in front of the OEM halo) & have a very short helmet height anyway.

Back to the point, if you absolutely do not want a cage for some reason, stick to a 4 point harness as your posterior chain must be able to shift down and forwards under a rollover condition; the OEM roof structure is in no way suitable to maintain its shape in track speed incidents. You *WILL* die or be severely disabled in this scenario with a 6 point because your spine & pelvis are fixed in all directions.


See also: https://www.corvetteforum.com/forums...67&postcount=9

Racingswh

Somehow I don't think you're going to be able to convince Mordeth not to wear his 6-point harness.

How many real world crashes have you been in to test your theories?

carefulnow

None, fortunately! But here are a few questions for you...
Have you ever seen a professionally built road race car with 5+ pt driver harness that doesn't have a roll cage?
Have you considered why even SCCA Solo rules require a roll cage if you do not use factory body restraints in open top or convertible cars?
Do you believe that the C6/C7 platform's a-pillar/roof/halo structure is sufficiently strong to prevent roof collapse in a high speed rollover accident?



Don't take my word for it though...

https://www.thetruthaboutcars.com/20...-safety-facts/
http://www.tracktuned.com/feed/2016/...oughts-on-them
https://www.rx7club.com/2nd-generati...street-203283/

Although if you're going to defensively castigate the concern as 'just a theory', it might be you who I can't convince of anything.

Racingswh

In my years of doing this I have been witness to, associated with as Safety Chair for our club for 5 years and involved personally in many crashes. Of all only two ended with serious injury and one of those was a fatality. In the fatality the Driver was wearing the 3 point factory belts without neck restraint and it was a straight on accident into the barrier in T6 at WG, a single car crash. The second was also a 3 point factory belt where the Driver was in a rearward impact into a tire wall and the seat back failed sending them into the rear of the vehicle while it was still traveling at a fairly high rate of speed.

In every other incident during my time participating in track and racing events for 27 years the number of crashes is probably in the many hundreds (5 of my friends crashed just two weekends ago). Except for one where my friend went into the trees (racing, full cage so I guess that makes 3 crashes where Driver's were seriously injured or killed), if the Driver was properly belted in with a 5 or 6 point harness, cage or no cage, all of the Driver's and Passenger's emerged essentially uninjured.

I have witnessed an end over roll over directly in front of me where the vehicle finally landed squarely on it's roof, my Wife destroyed our C6GS when she barrel rolled it 4 times after a front left GM brake line failure and at one point smashed down squarely on the roof, my best friend flipped our personal car onto its roof in a high speed accident and we have had 2 roll overs in our club that I can recall. 4 of the 5 had no cage. Each driver was fine. None of the roof lines caved in to any significant degree. My Wife was belted into her GS as firmly as possible in her 6 point because I did it myself. She is 5'10". I have "heard" a wicked crash without a cage to the point I was afraid to go look. Driver and Instructor popped out of that mangled C5 without a scratch, no cage, properly fastened 6 point belts with their neck restraints on. I am not sure they would have stayed inside the car without being belted in?

On a racetrack I now and will continue to belt myself in as firmly as possible into the vehicle that I am in using all of the restraint equipment available. I will absolutely be using a 6 point harness and proper neck restraint whenever I can whether the car has a roll cage or not. I of course wish all cars on the track had properly designed roll cages but am aware that it's just not practical for Driver's at the track that are there to enjoy their street cars.

Converted_Germ

I can attest to using a harness without a roll bar. I rolled my C5Z on the street while using TeamTech 6pt harnesses, BK harness bar, Sparco Evo2 and a custom seat mount. Everything worked perfect! EMTs said I would have broken my neck if i wasn't using the harness (kept my head off of the roof),

There's your real world experience.